Let \(P\)  be the uniform probability measure on \(\Omega = \lbrace 1,\ldots ,n\rbrace \) , for some positive integer \(n\) . Let \(X,Y\)  be random variables on the probability space \((\Omega , P)\) . Without any loss of generality, we assume that \(X\)  and \(Y\)  are mapping from \(\Omega \)  to sets consisting of consecutive integers, starting from 1.
Denoting by \(H\)  the entropy, the mutual information between \(X\)  and \(Y\)  is defined by [1]}:
\(I(X, Y) = H(X) + H(Y) - H(X,Y).\) 
